On a road they typically have an underlayment that has to be packed to withstand trucking. There are usually also new street lights, and sidewalks. In my area

On a road they typically have an underlayment that has to be packed to withstand trucking. There are usually also new street lights, and sidewalks. In my area they plant trees either in the median or between the sidewalk and the road. When you factor in the cost of those changes, 1.5 million seems reasonable for roughly a mile of road.